Activation of protein kinase C delta by the c-Abl tyrosine kinase in response to ionizing radiation

The c-Abl protein tyrosine kinase is activated by ionizing radiation (IR) and certain other DNA-damaging agents. The present studies demonstrate that c-Abl associates constitutively with protein kinase C delta (PKCdelta). The results show that the SH3 domain of c-Abl interacts directly with PKCdelta. c-Abl phosphorylates and activates PKCdelta in vitro. We also show that IR treatment of cells is associated with c-Abl-dependent phosphorylation of PKCdelta and translocation of PKCdelta to the nucleus. These findings support a functional interaction between c-Abl and PKCdelta in the cellular response to genotoxic stress.     

Kinetics of DNA repair synthesis in guinea-pig pancreatic slices following in vitro exposure to N-methyl-N-nitrosourethane

In vitro exposure of guinea-pig pancreatic slices to NMUT resulted in an increase in hydroxyurea-insensitive 3H-TdR incorporation into DNA; this represents DNA repair synthesis following NMUT-induced DNA damage. The kinetics of this hydroxyurea-insensitive 3H-TdR incorporation suggest that the NMUT-induced DNA damage is largely repaired within 2 hours.     

Myocardial infarction as a complication of new interventional devices

Percutaneous transluminal coronary balloon angioplasty has been associated with acute myocardial infarction (MI) as a complication of the procedure. Abrupt closure, distal coronary embolization, intimal dissection, coronary spasm, and acute thrombosis are the principal etiologies. New interventional devices (stent, laser, and atherectomy catheters) have been introduced as alternatives or adjuncts to balloon angioplasty. With use of the New Approaches to Coronary Intervention Registry, the incidence, predictors, and outcome of MI as a complication of using these devices as the primary mode of intervention were studied. There were 3,265 patients from 39 participating centers in the cohort treated with new devices. MI was reported as an in-hospital complication of using new devices in 154 patients (4.7%), including Q-wave MI in 36 patients (1.1%), and non-Q-wave MI in 119 patients (3.6%). MI rates were not significantly different among all patients with devices in the cohort treated with atherectomy (directional, extractional, rotational), laser (AIS, Spectranetics) or the Palmaz-Schatz stent. Multivariate logistic regression showed that post-procedure MI was associated with multivessel disease, high surgical risk, postinfarction angina, and presence of a thrombus prior to the procedure. Prior percutaneous transluminal coronary angioplasty was inversely related to the incidence of MI. When a specific cause of MI could be detected, the main etiologies were: coronary embolus 16.9%, and abrupt closure 27.3%. Other major in-hospital complications were higher in the MI group than the non-MI group: death 7.8% versus 0.8% (p <0.001), and bypass surgery 13.6% versus 1.7% (p <0.001). At 1 year, mortality rates remain higher at 12.9% in the MI group versus 4.9% in the non-MI group (p <0.01). Despite different indications for the use of new devices, they were not predictors for MI with the exception of the rotablator. The incidence of MI (1.1% Q-wave, 3.6% non-Q-wave) was comparable to previously reported rates for balloon angioplasty. The occurrence of MI is associated with an increase in other in-hospital complications and a doubling of 1-year mortality.     

Specific synergy of multiple substrate-receptor interactions in platelet thrombus formation under flow

Eosinophils are known to express cytokines capable of promoting fibrosis. Interleukin-5 (IL-5) is important in regulating eosinophilopoiesis, eosinophil recruitment and activation. Lung IL-5 expression is elevated in pulmonary fibrosis, wherein the eosinophil is a primary source of fibrogenic cytokines. To determine the role of IL-5 in pulmonary fibrosis, the effects of anti-IL-5 antibody were investigated in a model of bleomycin-induced pulmonary fibrosis. Fibrosis was induced in mice by endotracheal bleomycin treatment. Animals were also treated with either anti-IL-5 antibody or control IgG. Lungs were then analyzed for fibrosis, eosinophil influx, chemotactic activity, and cytokine expression. The results show that a primary chemotactic activity at the height of eosinophil recruitment is IL-5. Furthermore, anti-IL-5 antibody caused significant reduction in lung eosinophilia, cytokine expression, and fibrosis. These findings taken together suggest an important role for IL-5 in pulmonary fibrosis via its ability to regulate eosinophilic inflammation, and thus eosinophil-dependent fibrogenic cytokine production.     

Role of farnesyltransferase in ABA regulation of guard cell anion channels and plant water loss

Desiccation of plants during drought can be detrimental to agricultural production. The phytohormone abscisic acid (ABA) reduces water loss by triggering stomatal pore closure in leaves, a process requiring ion-channel modulation by cytoplasmic proteins. Deletion of the Arabidopsis farnesyltransferase gene ERA1 or application of farnesyltransferase inhibitors resulted in ABA hypersensitivity of guard cell anion-channel activation and of stomatal closing. ERA1 was expressed in guard cells. Double-mutant analyses of era1 with the ABA-insensitive mutants abi1 and abi2 showed that era1 suppresses the ABA-insensitive phenotypes. Moreover, era1 plants exhibited a reduction in transpirational water loss during drought treatment.     

Interferon-induced protein 10 and interleukin 8. C-X-C chemokines present in proliferative diabetic retinopathy

From May through November 1997, 1,011 samples of raw milk from bulk storage tanks were examined for the presence of verocytotoxin-producing Escherichia coli of serogroup O157 (O157 VTEC) by immunomagnetic separation following selective enrichment. The samples originated from 1,011 different dairy herds located throughout the Netherlands. O157 VTEC was not isolated from any of the milk samples examined. Additionally, survival of O157 VTEC in raw and UHT-sterilized cow's milk at 7 and 15 degrees C was studied, both in the absence and presence of an activated lactoperoxidase-thiocyanate-hydrogen peroxide system (LPS). Results indicated that the O157 VTEC strain tested was able to grow in raw milk at 7 degrees C as well as at 15 degrees C. Naturally occurring amounts of thiocyanate and hydrogen peroxide in the raw milk tested were not sufficient to activate the LPS. Although the LPS exhibited an antimicrobial activity against O157 VTEC in LPS-activated sterilized milk, O157 VTEC populations were not (or not as obviously) reduced in LPS-activated raw milk. Possibly background microflora were more sensitive to the LPS than the O157 VTEC test strain. It was concluded that raw milk contaminated with O157 VTEC will remain a hazard if kept at 7 or 15 degrees C. Effective pasteurization and avoiding postpasteurization contamination are necessary to ensure the safety of milk.